Booze’s Secret Ingredient? Water

Yagi Studio/Getty Images

Distillers understand that the quality of their ingredients determines the quality of the booze. Kentucky bourbon-makers use commodity-sized truckloads of corn every day and still brag about their standards. The people making scotch say the same thing about barley. Some of them even say their yeast strains are special, precious colonies. More controversial, though, is the role of another critical ingredient: water. Distillers mix it in when they ferment (sometimes). It dilutes neutral grain spirits before re-distillation (sometimes). And when a spirit comes out of the barrel, water “proofs it down,” dilutes the alcohol level before sale.

So it’s interesting to see a rare example of experimentation with different types of water in the latest issue of Distiller, the trade magazine from the American Distilling Institute (one of the groups that represents craft distillers). A group of distillers made the same gin six times—starting with the same neutral grain spirit, flavoring it with the same botanicals (juniper, angelica root, lemon peel, etc.)—and using the same pot still. The only thing they varied was the water.

And wow, did they go deep: six different waters, each with a known component of dissolved solids—that’s the different kinds of ions you’d find in mineral waters. The numbers ranged from as high as 475 parts per million of dissolved solids (including a whopping 390 ppm of bicarbonate) in French mineral spring water to practically zero across the board in “demineralized domestic water” from England. That’s tap, basically. The acidity ranged from a tart pH of 5.46 (French again) to Icelandic volcano glacial water at a basic pH of 8.4.

The results? The French dissolved-solids bomb was “soft and clean, with some bright floral notes.” The Icelandic water had “a very short flavor profile” and “a cloying texture.” The winner, roughly, was the tap water. “Full-bodied, with a smooth texture that really fills the mouth,” was the verdict—strange, perhaps, for water with hardly anything other than hydrogen and oxygen stuck together. Now, this wasn’t a big, peer-reviewed, blinded experiment. No one did any gas chromatography on the resulting gins. And the tasters didn’t claim the differences were huge—but they were there.

Intuitively, it makes sense that different water would taste different. Even municipal tap waters vary widely. I would have thought distillation would level out those kind of differences—it is, after all, a technology that turns salty seawater into something potable, so clearly it takes out dissolved salts. But as Kris Berglund, a chemical engineer who teaches distilling at Michigan State University, pointed out to me, the use of the water in the distillation process might have been less important than its use to proof down the gin for bottling. The tasting panel didn’t taste the cask-strength gin to compare.

I emailed the article to Darcy O’Neil, who includes a bunch of recipes for using minerals to mimic famous waters in his invaluable cocktail history book Fix the Pumps. He wrote back: “Higher mineral content, and the associated pH changes, can have an effect on the solubility of organic materials (essential oils from botanicals), though I’m not sure we could perceive it.” And he made another good point: Even in gin, salt enhances flavor.